Knowledge of the magnitudes of stresses in the earth's crust is fundamental to a broad range of problems of lithospheric mechanics. This is a project to make in situ stress measurements to ~10 km depth in the KTB scientific drillhole in cooperation with the University of Karlsruhe. It has never before been possible to measure in situ stress at nearly mid-crustal depth. If such measurements are successful, it will provide the opportunity to test such fundamental concepts as the hypothesis that stress levels in the brittle crust are in equilibrium with frictional strength as defined by simple faulting theory and laboratory-determined values of the coefficient of friction. In a related collaboration with the University of Karlsruhe (and Geoforschung Zentrum (GFZ), in Potsdam, Germany and the U.S. Geological Survey), the Principal Investigator will implement a new research program in eastern Europe to measure in situ stress orientation and heat flow (as well as other geophysical measurements) in boreholes in eastern Europe and the former Soviet Union. The basic idea of this research is to utilize a nearly- new (and nearly fully-outfitted) geophysical logging system acquired by GFZ for use in existing boreholes. In situ stress orientation will be determined from detailed analysis of borehole televiewer measurements. Over time, these measurements will help fill an extremely large gap in knowledge of stress orientations and relative magnitudes. The U.S. Geological Survey will collaborate in this effort as will investigators from the countries in which the holes are located.
